Capstan block



Feb. 18, 1941. c, BRUESTLE 2,232,206

' CAPSTAN BLOCK 7 Filed Sept 12, 1939 lNVENTOR U/WL 0.955715 Patented Feb. 18, 1941 UNITED STATES PATENT OFFICE Elevator Supplies Company, Incorporated,

Rahway, N. J a corporation of New Jersey Application September 12, 1939, Serial No. 294,459

3 Claims.

This invention relates to improvements in capstan blocks or pulleys for wire drawing machines and the like, and provides improvements therein.

In these machines, there is usually a plurality of drawing dies, with a block for each die. The peripheral speed of the blocks is progressively greater in sequence with the dies in consequence of the increments of wire-speed due to elongation as the wire passes through each die. The

' machines, particularly those for drawing the smaller sizes of wire, are designed however so that there is a certain amount of slip between each capstan block and the wire. This is to prevent the full pulling force of the block being exerted on any flight of wire between a die and a block, which would be apt to break the wire. At

the same time the amount of slip must be limited, particularly in high speed machines, so as to avoid burning, abrading, etc. of the wire.

The blocks are usually made with a plurality of drums or pulleys mounted on a single spindle, the drums being of different diameter to give the different peripheral speeds desired.

The aforesaid slipcauses wear and grooving of the drums or pulleys. They can stand only a certain amount of refinishing before the diameter is reduced to a degree where the slip becomes excessive. Moreover, refinishing the blocks is comparatively expensive and necessidrical form and a firm solid bearing surface maintained, and which conform to the conditions of operation, such as heat expansion, torque conditions etc. in a way to provide a pulling surface which does not detrimentally aifect the wire running thereon.

An embodiment of the invention is illustrated in the accompanying drawing, wherein:

Fig. 1 isa transverse section through the block and the spindle.

Fig. 2 is a plan View of a strip facing the block, on which the wire makes contact and which sustains the wear.

Fig. 3 is a side elevation of the Strip shown in Fig. 2 in the form of a circle.

Figs. 4 and 5 are respectively, a side elevation and vertical section of one of the cheek plates forming a part of the capstan block.

Referring to said drawing, numeral I0 indicates a rotary spindle, which is driven by means 7 not shown. A pulley or block I2 is secured on the spindle I0 so as to rotate therewith. The

block I2 may have one or more cylindrical portions constituting the drums or pulleys around which the wire runs. Three such cylindrical portions I4, l5 and I6 are shown. The wire does not contact directly with the cylindrical portions I4, I5, IE but with tires I8, I9 and 20. These tires are strips of hardened steel or the like, which encircle the cylindrical portions I4, I5 and I6 and fit closely and firmly thereon.

The strips 25 have a length corresponding very closely to the circumference of the surface of the cylindrical portion I4, l5, or IE on which they rest, and are preferably formed as very true circles. The ends 26, 21 of the strip- 25 do not quite meet, and when secured in place on the cylindrical surface I4, I5, I6 of the drum do not quite abut, a gap on the order of a few thousandths of an inch or so being left between the ends. The outer edges of the strips at the ends are also slightly rounded so as to remove any burrs and to dull the edge. The ends 26, 21 are not connected in use, and the width of the gap between these ends 26, 21 should be such that expansion of the strip by heat brings the ends just about together without one end being forced against the other. Thereby the arrangement is such that the expansion of the strip by heat will not bring about a reaction of forces between the ends which will tend to force the strip from close contact with the surface of the cylindrical portion I4, I5 or IE on which it rests, and thereby get out of round even slightly.

Means are provided for fastening the strips 25 firmly to the block, so that they will firmly withstand slipping on the block against the comparatively strong torque which is exerted through the spindle and block, against the pull of the wire thereon which is being drawn through a die. For this purpose an edge of the strip may be provided with one or more notches 30. Matching these notches 3!] are projections or pins 33 on the block. The projections or pins fit closely in the notches 30, and hold the strip 25 firmly against the torque of the block. v

In order to provide a smooth surface on which the wire may run, and also to avoid any crevices between the block and the circumferential edges of the strips in which wires of small diameter may catch the circumferential edges of the strip 25 are fitted into lateral grooves in the block faging each edge of a strip. In order to readily replace worn tires or strips 25 a cheek piece 36 is provided which is capable of being moved axially with relation to a side of a pulley or block. In a stepped pulley or block such as here shown,.the intermediate cheek pieces 31, 38 are grooved on two sides, thereby performing the dual function of receiving the adjacent edge portions of the two strips 25 corresponding to the diameters of two cylindrical portions I4, I5, I6. The notched marginal portions of the tire strips are thereby covered by the grooved portions of the block or cheek-pieces. The grooves have diameters corresponding to those of the tire strips which fit into them. The wall of each groove which lies closest to the axis of the drum has a diameter which is less than the diameter of the cylindrical portion of the drum (I4, I5 and I6) on which the tire strip rests, so that under all conditions the tire strip is seated firmly and solidly against the aforesaid cylindrical portion. This condition may be obtained by undercutting each groove, as shown.

The intermediate cheek pieces 31, 38 are illustrated, in Figs. 4 and 5. These cheek pieces, 31 for example, have a central opening 48 having a diameter corresponding to the diameter of one of the cylindrical portions of the block, as for example the cylindrical portion I4. Adjacent the opening 40 is a circular groove 42 corresponding in width to the thickness of the strips 25, and having a depth slightly greater than the depth of the notches 38 in the strip. The groove 42 serves to receive and confine the notched edge of the strip and the notched marginal portions of the tire strips are thereby covered by the cheek-piece. The cheek pieces adjacent the opening 48 also have semi-circular grooves 44 therein which register with and fit over the pins or projections 33 which project into the notches 38 of the strip 25. The intermediate cheek pieces, as for example the piece 31, have outer peripheral portions 46 which have a diameter somewhat greater than that of the diameter of the-step next to that on which it bears and which acts as a cheek at the side of the pulley or drum. In this peripheral portion 48, on the side of the cheek piece which is opposite to that which has the groove 42 formed therein is another groove 58 having a maximum diameter corresponding to the diameter of a strip 25 resting firmly against a cylindrical portion of the block, as the cylindrical portion I5. The groove 50 receives and confines an edge of the strip 25, which may be an unnotched edge thereof. This groove is also somewhat undercut, as illustrated and heretofore described, to facilitate the assembly of the parts and the firm bearing of the tirestrip on the cylindrical portion of the drum. The check piece 38 has a central opening 48 of larger diameter than that in the cheek piece 31, to enable it to fit on the cylindrical portion I5 which is of larger diameter than the cylindrical portion I4; otherwise it may be similar in construction to that of the cheek piece 36. The central opening 53 of the cheek piece 38 may have a diameter corresponding to that of the spindle I2, and in assembled position may rest thereon. This cheek piece 36 is provided with a groove 55 into which the edge of the strip 25 which bears on the cylindrical portion I4, projects, and by which it is confined. This cylindrical groove 55 is also somewhat undercut similarly to the groove 58 of the cheek pieces 31, 38.

For convenience in manufacture, the block I2, adjacent the cylindrical portion I8 may be provided with a separately formed cheek piece 51 which is fastened against the outer face of the block by suitable means; bolts 58 for example. Notches 44, similar to those in cheek-piece 31 may be formed therein, and also a circular groove 42 similar to that in said cheek piece may be provided for receiving an edge portion of the facing strip 20.

To facilitate assembly one end of the spindle may be threaded as indicated at 80, and a threaded nut BI provided thereon. A shoulder 63 is advantageously formed on the spindle, to sustain the thrust of the nut 6|.

To replace one or more worn tires I8, I9, 28 (strips 25) the nut 6I is loosened so as to release the block I2. The block I2 is then slid longitudinally thereby allowing separation of the block from a cheek-piece or from the cheek pieces 36, 31, 38. It is most efiicient in replacing the tires to remove the block with cheek pieces 31, 38 thereon. The cheek piece 31 may then be slid off of the cylindrical section I4 carrying the tire I8 with it. Then the cheek piece 31 may be slid off of the cylindrical portion I5 carrying the tire IS with it. The tire I8 is then free to he slid off of the cylindrical portion Hi.

In practice when it is necessary or desirable to replace one tire, it would be well to replace all of the tires. To do so a new tire 28 is placed on the cylindrical portion I8 and the edge having the notches 38 therein slid into the groove 42 of the cheek-piece 51 so that the pins or projections 33 fit into the said notches. The cheek piece 38 is then placed on the cylindrical portion I5 and slid against the tire 20 so that the adjacent edge thereof enters the groove 50 and bears against the bottom of the groove. A tire I9 is then placed on the cylindrical portion I5 and its edge having the notches 38 therein, slid into the groove 42 with the pins 33 entering the notches 3D. The cheek piece 31 is then slid over the cylindrical portion I4 and against the adjacent edge of the tire I9 so that the edge enters the groove 50 therein. The tire I8 is then placed on the cylindrical portion I4 and the edge portions of the tire I8 entered into the grooves 42 and 55 of the opposite cheek pieces 31 and 38. The nut 8| is then tightened against the block I2. The pressure of the nut forces the tire I8, I9 and 28 against the bottoms of the grooves in the respective cheek pieces. The pressure is transmitted through the tires and cheek pieces to the cheek piece 53, which bears against the shoulder 63 on the spindle, the bearing as here shown being through a collar 10 and an inner ring of a ball bearing 15. In the fully seated position of the tires I8, I9 and 28 there is advantageously a slight clearance between the sides of the cheek pieces and the sides of the block as indicated at 65 so that the thrust of the nut 6| on the block I2 will be transmitted through the tires 20, I9 and I8 and the cheek-piece 38 to the cheek piece 31 which sets against the shoulder 83, the seating as here shown, being through the collar 18 and the inner ring of the ball bearing 15. The undercut grooves 42, 50 assure the firm seating of the tire-strips 25 on the respective cylindrical portions I 4, I5, I8 oi the drum, or to be pressed firmly thereagainst if not so seated at the time of assembly. The foregoing construction and arrangement provides a simple way of assembling the separated parts and holding them tight in assembled p0 1. tion. However, the cheek pieces could be held against the sides of the block and against the edges of the tire strips otherwise than through the action of the nut BI and the joint action of the tires and cheek pieces.

The pulleys or blocks may serve for other uses than that described and the invention may receive other embodiments than that herein we cifically illustrated and described.

What is claimed is:

l. A capstan block or the like, comprising a cylindrical portion and a replaceable tire on said cylindrical portion, with which wire makes contact, said replaceable tire being a flat strip of wear resisting metal having a length slightly less than the circumference of said cylindrical portion when fitted closely thereon, so that said strip may lengthen slightly without buckling under thermal expansion, cheek-pieces at opposite edges of said tire-strip, circular grooves in said cheek-pieces into which the opposite edges of said tire-strip extend so that a marginal portion of said tire-strip is covered by a cheek-piece, said grooves having the wall thereof which is closer to the axis of the drum of a diameter less than the diameter of the cylindrical portion of the block on which the tire-strip bears, so that said tire-strip may bear firmly and uniformly on said cylindrical portion, the marginal portion of said tire-strip, within the area covered by said cheek-piece, having notches therein, and projections covered by said cheek-pieces, extending into said notches, for preventing slip between said tire-strip and the cylindrical portion on which it bears.

2. A capstan block according to claim 1, wherein said block has a plurality of cylindrical portions of different diameters thereon, and further comprising a plurality of cheek-pieces having central openings having diameters corresponding to the diameters of the plurality of said cylindrical portions of the block, said cheek-pieces having grooves on opposite sides thereof of different diameters into which edges of tire strips on cylindrical portions of different diameter fit.

3. A capstan block or the like, comprising an arbor, a shoulder on said arbor, a part having a plurality of cylindrical portions of different diameter, and a replaceable tire on each of said cylindrical portions with which wire makes contact, said replaceable tires each being a flat strip of wear resisting metal having a length slightly less than the circumference of its cylindrical portion when fitted closely thereon, so that each strip may lengthen slightly without buckling under thermal expansion, cheek-pieces at opposite sides or edges of each tire-strip, a plurality of said cheek-pieces being separable, and having central openings corresponding in diameter to the diameters of said cylindrical portions, said part having said cylindrical portions thereon and said cheek-pieces being movable axially of said arbor, said cheek-pieces having circular grooves into which the opposite sides or edges of said tirestrips extend so that the marginal portions of said tire-strips are covered by said cheek-pieces, each of said grooves in said cheek-pieces having its wall which is closest to the axis of the drum of a diameter less than the diameter of the cylindrical portion of the block on which the respective tire-strip bears, so that each of said tirestrips may bear firmly and uniformly on its cylindrical portion, the marginal portion of each tire-strip within the area covered by a cheekpiece, having notches therein, and projections covered by said cheek-pieces, extending into the notches in the marginal portions of each of said tire-strips, for preventing slip between said tirestrips and the cylindrical portions on which they bear, each of said tire-strips having a width exceeding the width of the cylindrical portion on which it bears plus the depth of each groove into which its marginal or edge portions extend, so

as to provide a clearance between each cheekpiece and the side of the cylindrical portion adjacent thereto, and a nut on said arbor acting against said part having the cylindrical portions thereon to transmit thrust through-the assembled tire-strips and cheek-pieces to said shoulder on said arbor.

CARL O. BRUESTLE. 

